Minecraft-Phantom-Panel/Agent/Phantom.Agent.Services/Backups/BackupServerCommandDispatcher.cs

using System.Text.RegularExpressions;
using Phantom.Agent.Minecraft.Command;
using Phantom.Agent.Minecraft.Instance;
using Phantom.Utils.Runtime;
using Serilog;

namespace Phantom.Agent.Services.Backups;

sealed partial class BackupServerCommandDispatcher : IDisposable {
	[GeneratedRegex(@"^\[(?:.*?)\] \[Server thread/INFO\]: (.*?)$", RegexOptions.NonBacktracking)]
	private static partial Regex ServerThreadInfoRegex();

	private readonly ILogger logger;
	private readonly InstanceProcess process;
	private readonly CancellationToken cancellationToken;

	private readonly TaskCompletionSource automaticSavingDisabled = Tasks.CreateCompletionSource();
	private readonly TaskCompletionSource savedTheGame = Tasks.CreateCompletionSource();
	private readonly TaskCompletionSource automaticSavingEnabled = Tasks.CreateCompletionSource();

	public BackupServerCommandDispatcher(ILogger logger, InstanceProcess process, CancellationToken cancellationToken) {
		this.logger = logger;
		this.process = process;
		this.cancellationToken = cancellationToken;

		this.process.AddOutputListener(OnOutput, maxLinesToReadFromHistory: 0);
	}

	void IDisposable.Dispose() {
		process.RemoveOutputListener(OnOutput);
	}

	public async Task DisableAutomaticSaving() {
		await process.SendCommand(MinecraftCommand.SaveOff, cancellationToken);
		await automaticSavingDisabled.Task.WaitAsync(cancellationToken);
	}

	public async Task SaveAllChunks() {
		// TODO Try if not flushing and waiting a few seconds before flushing reduces lag.
		await process.SendCommand(MinecraftCommand.SaveAll(flush: true), cancellationToken);
		await savedTheGame.Task.WaitAsync(cancellationToken);
	}

	public async Task EnableAutomaticSaving() {
		await process.SendCommand(MinecraftCommand.SaveOn, cancellationToken);
		await automaticSavingEnabled.Task.WaitAsync(cancellationToken);
	}

	private void OnOutput(object? sender, string? line) {
		if (line == null) {
			return;
		}

		var match = ServerThreadInfoRegex().Match(line);
		if (!match.Success) {
			return;
		}

		string info = match.Groups[1].Value;

		if (!automaticSavingDisabled.Task.IsCompleted) {
			if (info == "Automatic saving is now disabled") {
				logger.Debug("Detected that automatic saving is disabled.");
				automaticSavingDisabled.SetResult();
			}
		}
		else if (!savedTheGame.Task.IsCompleted) {
			if (info == "Saved the game") {
				logger.Debug("Detected that the game is saved.");
				savedTheGame.SetResult();
			}
		}
		else if (!automaticSavingEnabled.Task.IsCompleted) {
			if (info == "Automatic saving is now enabled") {
				logger.Debug("Detected that automatic saving is enabled.");
				automaticSavingEnabled.SetResult();
			}
		}
	}
}